Pull means for tear strip

ABSTRACT

The present invention relates to pull means for an easy opening container that includes an end panel provided with a weakened score line defining a tear strip. The pull means acts in the manner of a second class lever and fulcrum action on the tear strip to initiate tearing the tear strip. The pull means includes an end portion having an opening which receives a connecting member interconnecting the pull means with the tear strip and further includes a pair of spaced parallel ribs which are transversely spaced from a plane defined between the axis of the opening and the point at which an opening force is applied to the pull means. The spaced parallel ribs dissipate the forces from generally straight line paths from the edge of the end portion which defines the fulcrum, to a major area of the end portion so as to prevent a weakening of the end portion along the straight line paths which may cause elongation of the opening in the pull means.

nited States Patent [72] Inventors Richard D. Zenger Downers Grove;

Audie 1L. Lambert, Rosemont, botlh 0t llll. 21 Appl'. No. 858,454 [22]Filed Sept. 16, 1969 [45] Patented lDec. M, 1971 [731' Assignee NationalCan Corporation Chicago, Ill.

[54) lPUlLlL MEANS FOR YEAR STRIP ll ttulms, 5 ihmwlnm Fins.

i 1 220/54 [5 l] B65d17/24 [50] 220/54, 27. 53, 48

[56] References Cited UNITED STATES PATENTS 3,381,848 5/1968 Brown220/54 3,401,822 9/1968 Fraze 220/54 3,439,833 4/l969. Fraze 3,445,0295/1969 Zenger Primary Examiner-George T. Hall Attorney-Robert J. DohertyABSTRACT: The present invention relates to pull means for an easyopening container that includes an end panel provided with a weakenedscore line defining a tear strip. The pull means acts in the manner of asecond class lever and fulcrum action on the tear strip to initiatetearing the tear strip The pull means includes an end portion having anopening which receives a connecting member interconnecting the pullmeans with the tear strip and further includes a pair of spaced parallelribs which are transversely spaced from a plane defined between the axisof the opening and the point at which an opening force is applied to thepull means. The spaced parallel ribs dissipate the forces from generallystraight line paths from the edge of the end portion which defines thefulcrum, to a major area of the end portion so as to prevent a weakeningof the end portion along the straight line paths which may causeelongation of the opening in the pull means.

Patented Dec. 14, 1971 3 27A VEN 70!?5 Mair! D1 Zelzger' 1122, Mgbm?BACKGROUND OF THE INVENTION The present invention relates generally tocontainers and more particularly to an improved pull means'for atear-out strip forming part of an easy open end of the container.

Containers having so called easy open ends have become well known in thepast several years and now enjoy a considerable measure of consumeracceptability. The easy open end container normally includes an endpanel which has at least one weakened line defining a tear strip whichis adapted to be removed to gain access to the container. The tear stripis generally removed from the end panel by pull means in the form of apull ring or tab which is affixed to a portion of the tear strip bymeans of a rivet. The rivet may be an integral structure forming part ofthe tear strip or alternatively may be a separate member with the rivetbeing received through an opening defined in an extension or end portionof the pull means. The end portion of the pull means has an edgedefining a fulcrum for the pull means including the end portion and ahandle portion connected thereto.

In such devices, when the tearing of the strip is initiated by a pivotalmovement of the pull or tab means, considerable difficulty has beenencountered in having the pull means separate from the tear strip withthe undesirable result of having the tear strip retained on the endpanel. The separation of the tear strip has been determined to be causedby elongation of the opening in the pull means or in some cases,fracture of the end portion of the pull means. While one solution tothis problem would be to increase the thickness of the material formingthe pull means, such a solution is not commercially feasible because ofthe increased material cost for the pull means.

BRIEF SUMMARY OF THE INVENTION This invention relates to a containerhaving an easy open end including a tear strip connected to a pullmeans. The pull means includes a handle portion and an end portion withan opening in the end portion receiving connecting means forinterconnecting the tear strip and the pull means.

Applicants have determined that the primary cause for the weakening andsubsequent fracturing of the end portion along a line between theopening and the fulcrum edge results from a concentration of forces at asmall area located adjacent the opening and remote from the fulcrumduring the initial pivotal movement of the pull means. Thisconcentration of forces develops from lines of force propagating fromthe fulcrum points for the pivotal movement toward the opening and ithas been determined that the propagation occurs along substantiallystraight line paths from the fulcrum towards the handle of the tab.Thus, a very small area of the end portion must be capable of absorbingall of the forces which are concentrated as a result of the initialpivotal movement of the pull means.

The present invention contemplates distributing this concentration offorces away from the substantially straight line paths of propagation toa major portion of the end portion of the pull means.

According to the illustrative embodiment of the present in vention, theforce distributing means on the end portion is in the form of a pair ofelongated ribs which extend substantially parallel to each other and aretransversely spaced from a plane defined between the axis of the openingand the point of application of the opening force which tends to pivotthe pull means about the axis defined by the fulcrum. The ribs ormembers extend substantially the entire length between the edge definingthe fulcrum and the edge of the handle portion of the pull means. Thus,the force distributing ribs intersect the straight line path ofpropagation of the forces and result in a distribution of these forcesover the major area of the end portion. The redistribution of the forcesover the major area of the end portion of the pull means prevents aweakening of the end portion along a line or lines between the openingand the fulcrum edge so as to preclude elongation of the opening asufficient amount to allow the connecting means to slip out of theopening.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. I of thedrawings discloses a fragmentary top perspective view of a containerhaving an easy open end with the present invention incorporated therein;

FIG. 2 is a plan view of the easy open end of the container shown inFIG. 1;

FIG. 3 is an enlarged fragmentary plan view of the tear strip and thepull means;

FIG. 4 is an enlarged sectional view taken generally along lines 44l;and

FIG. 5 is an enlarged sectional view taken generally along lines 5 ofFIG. I.

DETAILED DESCRIPTION While this invention is susceptible of embodimentin many different forms, there is shown in the drawings and will hereinbe described in detail, one specific embodiment with the understandingthat the present disclosure is to be considered as an exemplification ofthe principles of the invention and is not intended to limit theinvention to the embodiment illustrated.

FIG. I of the drawings illustrates a container or can 10 having a bodyI2 which has the lower end thereof (not shown) closed in the normalmanner by either an integral end or an end separately secured thereto.The upper end of the container body I2 is closed by means of an easyopen end, generally indicated by the reference numeral I4, which issecured to the container body 12 by means of a conventional double seam16.

The easy open end I4, which is a readily workable material such asaluminum, includes a continuous score line 18 which defines a tear-outsection or removable tear strip 20 having a tear initiating orconnecting end 22. The tear initiating end or portion 22 is connected topull means 214 through connecting means which is illustrated as anintegral rivet 26. The integral rivet 26 extends through an opening 28located in a well 29 defined in an end portion 30 forming part of thepull means 24 and the rivet 26 is flattened to overlie the upper surfaceof the pull means. The well 29 further includes a handle portion 32,which is illustratively shown as a ring having the end portion 30integral therewith and extending from one edge thereof. As clearly shownin FIG. 5, the ring 32 is formed by doubling over the material. The endportion has an edge 34 which has segments 35 on opposite sides foldedunder the main body of the end portion. The free ends 36 of the foldedportions 35 define fulcrum points during removal of the tear strip.

In removing the tear strip 20 from the remainder of the end panel, thehandle portion 32 of the pull means is pivoted about fulcrum points 36on the end portion 30.

During such pivotal movement of the pull means 24, considerable problemhas been encountered in having the opening 2% elongate a sufficientamount to allow the rivet to pass through the opening and thereby allowthe pull means to be removed from the tear strip 20 prior to completeremoval of the tear strip from the end panel of the container. Furthermore, in some cases, it has been found that the end portion will befractured along a line between the edge of the opening 2% and the edge34 of the end portion 30..

Applicants have determined that the elongation of the opening 2% and/orthe fracture of the end portion is caused by a concentration of forcesalong a portion of the opening which is remote from the fulcrum or edge34. This concentration of forces, identified by the reference f,develops from the forces that tend to propagate along generally straightline paths from the outer edge 34 of the end portion 30. Inspectionshave shown that the lines of propagation of forces are generallystraight line paths extending from the points of contact of the endportion of the tab and the end 14. The lines of propagation are locatedon either side of the opening 28 and extending from the edge along linesidentified by reference numerals, a and b. This propagation of forcesalong narrow substantially straight lines from the edge of the endportion 30 towards the handle 32 will tend to stress the metal of theend portion beyond its elastic limit thereby allowing the opening toassume an oval shape or, in some cases, cause a fracture along either ofthe lines a or b. In either instance, the configuration of the centralopening 28 is sufficiently deformed to allow the enlarged portion of therivet 26 to pass through the opening thereby resulting in a separationof the pull means from the tear strip prior to complete removal of thetear strip.

' The condition described 77 is further aggravated by the fact that thepivotal force on the pull means is generally applied at the remote endof the pull ring 32, identified by the reference numeral 0, whichproduces a bending of the end portion at a point between theconcentration of forces f, and the fulcrum points 36. These bend lines,have been determined to be located along the lines a and b.

According to the present invention, the end portion 30 incorporateselongated means for distributing the concentration of forces awayfromeither of the force lines a or b and dissipating these forces along anarea which is substantially parallel to and spaced from a plane locatedbetween the axis of the opening 28 and the point of application of theopening or pivotal force, identified by reference c.The forcedistributing means is illustrated as a'pair of ribs 40 which are spacedfrom and located on opposite sides of the opening 28 and extendsubstantially the entire length between the handle portion 32 and theedge 34. The force distributing means or ribs extend a sufficientdistance to intersect the normal lines of propagation, a or b, from theedge 34. Thus, the force distributing means or elongated ribs will tendto dissipate these forces across a major portion of the end portion 30to eliminate the possibility of developing a weakened line between theconcentration of forces f and the edge 34. The elongated ribs 40 furtherresist bending of the end portion along the plane defined between thefulcrum, and the point of application of ivotal force.

Actual tests have shown that the most desirable disposition of theelongated ribs 40 is to have the ribs extend parallel to each other andspaced from the edge of the opening 28 with the axis of the respectiveribs extending substantially parallel to the plane defined between theaxis of the opening 28 and the normal point of application of thepivotal force. These tests have also shown that the resistance tobending or fracture along either of the lines a or b during the pivotalmovement of the pull means 24 is increased a considerable amount byutilizing the force distributing means as illustrated. However, it wouldbe appreciated that the relationship of the force distributing means orribs 40 and the end portion may assume angles other than the parallelrelationship described. For example, the force distributing means couldbe disposed substantially parallel to the curled edge portions 35 of theend portion 30. Such an angular relationship of the ribs with respect tothe plane between the fulcrums and the point of application of forcewould still distribute the propagation of forces away from the generallystraight line path and dissipate these forces over the major portion ofthe end portion 30.

The particularly pull means have been found to increase the resistanceto bending and/or fracture by as much as 30 percent thereby allowing acontainer manufacturer to reduce the thickness of the metal utilized forthe pull means from the thickness of the metal which was heretoforeconsidered necessary to prevent the bending and/or fracture of the endportion during the initial pivotal movement of the pull means toinitiate tearing of the strip 20.

What is claimed is:

1. Pull means for removing a tear strip from an end panel of a containercomprising a handle portion for exerting a force on said tear strip; andend portion extending from said handle portion, said end portionterminating in an edge spaced from said handle portion and definingfulcrum points on said end panel for said pull means, said end portionhavin an opening receiving a connecting portion of said tear strip orinterconnecting said tear strip and pull means; said end portion havinglines of forces developed therein when an opening force is applied tosaid handle portion said lines of forces extending from said fulcrumpoints toward said opening; and a pair of force distributing ribs onsaid end portion and extending substantially between said edge and saidhandle means, said force distributing ribs respectively intersectingsaid lines between said opening and said edge to disperse said forcesacross a major portion of said end portion.

2. Pull means as defined in claim 1 in which said force distributingribs extend substantially parallel to each other and to a plane definedbetween the axis of said opening and the point of application of theopening force on said handle means.

3. Pull means as defined in claim 2, in which said ribs are formed bydeforming said end portion.

4. In combination with a container having an aluminum end panel, saidend panel having a weakened line defining a removable tear strip, saidtear strip having a tear initiation end; pull means having a handleportion and an end portion extending from said handle portion; said endportion having an edge defining fulcrum points overlying said panel andan opening between said edge and said handle portion; connectingmeansreceived through said opening and interconnecting said tear initiatingend and said end portion; and a pair of parallel elongated ribs disposedon opposite sides of said opening and between the fulcrum points andsaid opening, said ribs being spaced from said opening and extendingsubstantially the entire length of said end portion, said ribsdistributing forces over a major portion of said end portion which areconcentrated adjacent said opening and tend to propagate from said edgewhile initiating tearing of said tear strip from said opening byapplying a force to said handle means to prevent weakening of said endportion along a line between said opening and said edge which would tendto allow said opening to elongate.

1. Pull means for removing a tear strip from an end panel of a containercomprising a handle portion for exerting a force on said tear strip; andend portion extending from said handle portion, said end portionterminating in an edge spaced from said handle portion and definingfulcrum points on said end panel for said pull means, said end portionhaving an opening receiving a connecting portion of said tear strip forinterconnecting said tear strip and pull means; said end portion havinglines of forces developed therein when an opening force is applied tosaid handle portion said lines of forces extending from said fulcrumpoints toward said opening; and a pair of force distributing ribs onsaid end portion and extending substantially between said edge and saidhandle means, said force distributing ribs respectively intersectingsaid lines between said opening and said edge to disperse said forcesacross a major portion of said end portion.
 2. Pull means as defined inclaim 1 in which said force distributing ribs extend substantiallyparallel to each other and to a plane defined between the axis of saidopening and the point of application of the opening force on said handlemeans.
 3. Pull means as defined in claim 2, in which said ribs areformed by deforming said end portion.
 4. In combination with a containerhaving an aluminum end panel, said end panel having a weakened linedefining a removable tear strip, said tear strip having a tearinitiation end; pull means having a handle portion and an end portionextending from said handle portion; said end portion having an edgedefining fulcrum points overlying said panel and an opening between saidedge and said handle portion; connecting means received through saidopening and interconnecting said tear initiating end and said endportion; and a pair of parallel elongated ribs disposed on oppositesides of said opening and between the fulcrum points and said opening,said ribs being spaced from said opening and extending substantially theentire length of said end portion, said ribs distributing forces over amajor portion of said end portion which are concentrated adjacent saidopening and tend to propagate from said edge while initiating tearing ofsaid tear strip from said opening by applying a force to said handlemeans to prevent weakening of said end portion along a line between saidopening and said edge which would tend to allow said opening toelongate.